Electric heating system for street cars and the like



Oct. 8, 1929. w; G. HARTWIG ELECTRIC HEATING SYSTEM FOR STREET CARS AEDTHE LIKE 2 Sheets-Sheet l Filed Dec. 10, 1925 Patented Get. 8, 192%WILLIAM G. HAnTwIG, OF CHICAGO, ILLINOIS, ASSIGNQB T RAILWAY UTILITYooif- PANY, on CHICAGO, ILLINOIS, A CORPORATION or ILLINOIS ELECTRICHEATING SYSTEM non srnEn'rcARs AND THE LIKE Application filed December10, 1923. Serial No. 679,529.

- In the-system to which my invention relates flit isjcommon practice toconnect the heating elements in multiple and also to I arrange them ingroups, the members of each group being in series .and the groups beingconnected in multiple in the circuit of the heating. current. In suchsystem a. contactor isemploye'd to control the heating circuit,

, the contactor in turn being controlled by a thermostat which closesthe circuit when the temperature drops ,below a predetermined minimumand, opens the circuit when the temperature rises above a predeterminedminimum. v I It sometimes happens that one of the units or groups ofsuch a system becomes shortcircuited when a break occurs therein whichmay cause a fire or panic among the pas- H sengers. If one of the groupsor a heating 2 unit is out of commission the temperature of the car isaptto drop below that which it is required to maintain and it isdesirable in any event when the heating circuit becomes imperfect thatthe car be immediately shifted into'the shop for repair. It is theobject of the present invention to provide means for automaticallyopening the heatingv circuit in such contingencies and at the same timeindicating to the inspector or repairman where the trouble is located sothat he may lose no time in looking for it. With this in view I providean automatic cutout and indicating apparatus comprising electro-magneticcoils in the circuits of the respective heating units or groups of unitswhich will immediately open the contactor controlling the supply ofcurrent to all of the heaters or groups on failure of current to any ofthem and at the same time so set an indicator or detector 4.0 that thefaulty unit or group of units will be at once apparent. In the drawingsand in the following specification I have disclosed a preferredembodiment of my invention as applied to a thermostatically controlledelectric heating system in which the heaters are V v arranged intwogroups or serles; it isto be understood, however, .that' thespecificdis: closure is for the purposeof exemplification only and thatthe invention is applicable to 7 other systemsv andv arrangements ofheaters and may be embodied in other. formsthan that disclosed, comingwithin the scope ;of

the following claims in which ;-I-have en:

deavored to present the; invention in the broadest terms which the priorart will permit. A 5;

In the drawings accompanying and form;

ing a part of this specification, Fig. 1; is a front elevation of apreferredform of. my

invention adapted to a two unit or. group electric heating j system;Fig. i 21a top, plan view thereof; Fig. 3 a vertical transverse sectionthereof showing one solenoid and certain of the parts in one position;Fig ,4 {a similar section looking at the other solenoid with certain ofthe parts shown in a different posi'tiomand Fig. 5 a diagramofaather'mostatically controlled system embodying said form of theinvention. Each part isviolentified by thesame reference numeral in theseveral views. I J a Referring first to the diagram, Fig.5,the heatersare shown at 6 connected in two series 7 and 8, the supply of currentthereto being controlled by the contactor 9. It will. be

apparent hereafter :that with an obvious modification any number ofseries of heaters may be employed. "The electro-magnetic coil 10controlling the contactor is supplied with energizing current through acircuit from the source of the heating current (.ordie narily thetrolley supplying also themotor) at 12, comprising a suitable resistance13 and said coil 10 and grounded at 14:. A thermostat 15 short-circuitscoil 10 when the temperature in the enclosure being heated rises to thepoint for which the system is designed and set. The heating system asthus far; de.-

scribed is one of those in practical use to which my invention 1sapphcable.

In applying my invention to such a system controller coils of thecombined cutout and indicator to be presently described are included inthe circuits of. the respective heater groups at l6, l7 and preferablybetween said groups and the ground 19, so that when the heating currentis on in the series of heaters 7 the solenoids 16 will be energized andwhen the current is on through the series of coils 8 solenoid 17 will beenergized.

In normal operation these solenoid coils willbe energized andde-energized together and only when there-is a break in one of thebranch circuits will either coil be energized without the other.

The coils 16 and 17 are shown diagrammatically in Fig. 5 of the drawingsas coils of two-solenoids the cores l6 andl? of which together control aswitch 36 in a shunt about the coil 10 comprising the wires 0, d. Theactual construction as shown in Figs. 1 to 4 inclusive is such that solong as the solenoids are energized and Clo-energized together theswitch 36 remains open, but when one of the solenoids is energized whilethe other is de-energized the switch 36 is closed, thus shunting thecontactor coil 10 and opening the contactor controlling the supply ofheating current.

Referring now to Figs. 1 to 4 inclusive, the solenoids l6 and 17 areshown mounted vertically side by side on a sheet-metal support 23, theend flanges 24 of which are screwed to a panel 22. The solenoids aresecured to the sheet-metal support by yolres 25. An end of each coil 16,17 is secured to an individual binding post 26, 27 from which connectionmay be made to the respective heater groups. The other ends of therespective coils are connected to the strip 28 which may be connected toground by the binding post 29.

The core 30 of each solenoid is provided with a reduced extension or rod31 which extends above the upper end'thereof and carries an indicator 32by which the position of the solenoid core is readily observed. Theindicator isformed of sheet-metal comprising a horizontal portion 32through which the rod 31 extends and an apron 32 which extends down infront of the strap 25. The

apron is perforated as at 33 and'a band of distinguishing color 34 isput upon the yokes 25 at a height to be in register with the openings 33when the indicator and core are in their. lowermost positions. Thus theindicator shows the metal color of yoke 25 when the solenoid isenergized and the band 34: when the solenoid is de-energized. One end ofthe flat portion 32 of the indicator is bent up at 50 and horizontal at51 to form a shelf or The switch 36 in the shunt to the contact tor coil10, controlled by the solenoids is, in the illustrated form of theinvention, comprised of a stationary contact 37 and a movable contactarm 38. The former is mounted on, but insulated from, the support 23 andis connected by wire 39 to a binding post a. The movable arm 3-8 iskeyed to a rod or rock shaft 40 journaled between the arms of a pivotedcarrier or bail tl. Said bail is pivoted at 42 to brackets 43 secured tothe support 23 above mentioned and said brackets also comprise stopfingers 44 for limiting the upward movement of the bail. This arm 38 isin electrical connection with the support sheet 23 through rod 40, bailor carrier 41 and brackets 43, and the support sheet 23 is connected tobinding post e6. The bind ing posts 46 and a are connected to therespective terminals of the contactor coil by the wires 0 and cl. Therod 40 also carries a catch or latch 49 to cooperate with eachindicator, there being. in the present instance two of these catches.Each latch extends at its end into a hole 54 in the correspondingindicator plate and is provided with a notch. 55 which is in thehorizontal plane of said plate when the latter is in its upper position.Each latch is also provided with a shoulder which is above its indicatorplate when the latter is in its lowerf most position.v Each latch isalso formed with a shoulder 52 above which the ledge 51 of: theindicator plate extends, said ledge being clear of the shoulder when theindicator plate and core are in their uppermost 1.

ing discs 71, 71, which are engaged by the respective indicator plateswhen the latter are raised by their solenoid cores to lift the ball. Therod 40 is provided with a counterbalance, here shown as integral withthe contactor arm, at 4:5, to offset the weight of the latches andnormally hold the contactor arm 38 in substantially vertical positionand away from the stationary con-- tact 37.

The operation of the device will now be described. During normaloperation the sole- I noids will be energized and de-energized togetheras the heating current is turned on:

or oil by the contactor. When the current is on, the solenoid cores andindicators will, of course, be in their uppermost positions as will alsothe bail 41 and the parts carried thereby, the bail being supported inits uppermost position by the engagement of the discs 71 with the upperface of the indicator members 32. The latch members and contact arm willbe in substantially the position shown in Fig. 3. When current is outoff from both solenoids by opening of the contactor as in normaloperation the solenoid cores and indicators will drop until the ledges51 of the respective indicators engage the shoulders 52 of therespective latches. The weight of the solenoid cores and connected partsin further descent will carry down the latches and the bail, the latterswinging downwardly on its pivots 452, but the contactor arm will not beswung into contact with the fixed contact 37 because of thecounterbalance l5. lVhen the two solenoids are again energized togetherthey return to the positions shown in Fig. 3, lifting the bail andwithout substantial movement of the latches and movable contact aboutthe axis of rod 40. When, however, current through one of the solenoidcoils fails while the other remains energized the core of thede-energized coil drops, carrying with it its indicator. The ledge 51 ofthe falling indicator engages the shoulder 52 of the latch beneath itand the latter receives the pull of the weight of the core and attachedparts. The bail, however, is held in its uppermost position as before,by the core and indicator of the solenoid which has not beende-energized. The weight of the dropping core, therefore, exerted on theshoulder of the corresponding latch causes the latter, the rod 40 andthe contact arm 38 to swing about the pivots of rod 40 so that thecontact arm makes contact with the stationary contact 37 As will beobvious from an inspection of Fig. 3, before the ledge 51 of the fallingin'di cator engages the shoulder 52 of the corresponding catch the plate32 is beneath the level of the shoulder 70. The oscillation of the rod40 produced in the manner above described swings the other latch 49keyed thereto into the position shown in Fig. 4t, in which the notch 55thereof engages the corresponding indicator plate. Thus this indicatorplate is held in raised position even after the solenoid is de-energizedby the opening of the contactor through the closing of the shunt bymeans of the contact arm 38 and contact 37 The inspector observing thatone of the indicators is down while the other is up can readily locatethe trouble, the entire heating current having been cut off in themeantime.

In the event that one of the heater circuits becomes defective while theheating current is off the instrument will signal the difficultylikewise when the current is again turned on.

The energized solenoid will raise the bail but the weight of the coreand attached parts of the unenergized solenoid acting on thecorresponding latch will close the contact arm 38 against the stationarycontact and the indicator remaining down will give the properindication. The parts may be restored to normal position by key 56 whichengages the contact arm 38.

I claim:

i 1.111 ade ice at the 015st described,a piarality of solenoids thecores of which are independently movable, a vertically movable carrier,a switch member pivotedthe'retd ja stationarycontact, a pluralityofglatchesi'n fixed relation to said switch member and adaptedrespectively to engage and hold in the latter to sustain the weight ofthe respective coreswhereby when'on'e ofls'aid solenoids is de-energizedwhile the others remain energized the descent of its core swings thelatches and the contact arm to engage the stationary contact and whenall of the solenoids are deenergized the weight of the cores lowers saidcarrier.

' 2. In a device of the class described, a plurality of solenoids, thecores of which are movable from a lower to an upper position when therespective solenoids are energized, a carrier element mounted above thesolenoids and adapted to be engaged and raised by either of the coreswhen the solenoid thereof is energized, a rock shaft mounted on saidcarrier, a latch for each core mounted upon said shaft and adapted andarranged when the carrier and core are in the upper position 7 to engagesaid core and hold it in the upper position and also to be engaged bysaid core when the latterdrops to rock said shaft, and a switch, themovable element of which is likewise mounted on said shaft and adaptedto close against the stationary contact of said switch when said shaftis rocked.

3. In a device of the class described, a pair of solenoids the axes ofwhich are substantially vertical, cores for said solenoidsadaptindicator mounted on each solenoid core, and

adapted to engage and lift the bail when the indicator is raised, a rockshaft mounted in the bail, detents on the rock shaft adapted when thelatter is oscillated to engage the respective indicators, but normallyout of contact therewith, said detents being also arranged to be engagedby the respective indicators when the latter fall to rock the shaft, astationary contact and a movable contact, the latter'being mounted onthe shaft, whereby when the solenoids are energized and deenergizedtogether the bail is raised and lowered without rocking the shaft, andwhen one of said solenoids is deenergized and the other remainsenergized, the shaft is rocked to close the contact and engage theindicator of the energized solenoid.

a. In a device of the class described, a plurality of vertical solenoidswith vertically izo movable cores, a yoke pivoted above the sole- Inoids in the path of movement of the respective cores, and adapted to beraised thereby T30 4 mama,

1 H. 11 n a li $0 a lh fiin leawt ipq ifiimi; ean n each co e to engagethe ga t ch assoc iat ed therewith Whn the core ,f alls to s wing fthecatches and oscillatory .7 mmber ntqfin po io andflfswitch j ogcillatprymgmber and adapted to engage the fixfidlmfimb rth m fflf h n thbatches are W n ..t n gpo iti n-5 WILL M G- HA i

